A screwdriver is an example of a wheel and axle, which is a type of simple machine. The mechanical advantage of a wheel and axle is the ratio of the radius of the wheel to the radius of the axle. The force required to turn a screw can be reduced by
A) reducing the length of the axle.
B) increasing the radius of the axle.
C) reducing the length of the handle.
D) increasing the radius of the handle

Consider the particle-in-a-box problem in 1d. a particle with mass m is confined to move freely between two hard walls situated at x = 0 and x = l. the potential energy function is given as (a) describe the boundary conditions that must be satisfied by the wavefunctions ψ(x) (such as energy eigenfunctions). (b) solve the schr¨odinger’s equation and by using the boundary conditions of part (a) find all energy eigenfunctions, ψn(x), and the corresponding energies, en. (c) what are the allowed values of the quantum number n above? how did you decide on that? (d) what is the de broglie wavelength for the ground state? (e) sketch a plot of the lowest 3 levels’ wavefunctions (ψn(x) vs x). don’t forget to mark the positions of the walls on the graphs. (f) in a transition between the energy levels above, which transition produces the longest wavelength λ for the emitted photon? what is the corresponding wavele

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00ºc. note that this calculation is only approximate because ocean warming is not uniform with depth. (answer in ×10^{-3} −3 m)

Energy can be transformed from one form to another. the diagram shows one such process. which energy transformation is represented in the diagram? nuclear to thermal and radiant nuclear to electrical and chemical chemical to nuclear and radiant chemical to electrical and nuclear